This is a biobehavioral, longitudinal investigation of the role of emotion in the development of psychopathology in adolescence. The focus is on (a) the role of multiple components of negative emotions (anger, anxiety, sadness) in the evolution of psychopathology, and (b) socialization experiences and biological processes that contribute to emotion dysregulation and disorder. The dysregulated experience and expression of emotion is implicated in both externalizing (antisocial patterns) and internalizing (anxiety, depressed mood) disorders. Adolescence is a critical juncture in the development of these disorders. The incidence of psychopathology increases during this time period, and clinical problems become more differentiated along gender lines, i.e. more antisocial behavior in males and more anxiety and depression in females.Four groups of youths are studied: (1) comorbid externalizing and internalizing problems, (2) externalizing problems, (3) internalizing problems, and (4) asymptomatic. Youth range in age from 11 to 16 years and are studied at two time points, spaced two years apart. Equal numbers of males and females are studied in order to examine etiology of sex differences in symptoms, emotion regulation, and developmental changes in how disorders manifested. A multi-method, multi-respondent approach is used. Time 1 includes physiological and and neurohormonal functioning (ANS, HPA), behavioral observations of youth and family, experimental paradigms, structured psychatric interviews and questionnaires. Time 2 outcomes are based on interview and questionnaire methods. Data collection has just been completed for both time points so longitudinal analyses can now be conducted to determine predictors of psychiatric and psychological outcomes. At Time 1, neurohormonal patterns predict psychiatric symptoms differently for males and females: e.g. low testosterone levels are associated with anxiety/depression only in boys, while disruptive girls show a steep decline in production across the day. Analyses of DHEA (dehydroepiandrosterone) also identify important sex differences. Structural equation models estimated relationships between latent-anxiety-depression and disruptive behavior problem constructs and intra-individual differences in DHEA. DHEA levels were higher in females than males and were positively associated with age and pubertal development. DHEA levels decreased 29% from morning to mid-day and by 6% from mid-day to late afternoon. For girls, higher levels of anxiety-depression were associated with an increase in DHEA levels from mid-day to late-afernoon. DHEA reactivity tp social challenge was associated with anxiety-depression and disruptive behavior problems. The gender differences in DHEA levels differ from prevous findings of no differences for this sample in terms of their cortisol levels. This suggests that DHEA or the ratio of DHEA to cortisol may be more informative about potential sex differences in neurohormonal underpinnings of anxiety and mood disorders than will cortisol levels per se. In other Time 1 analyses, additional links between symptoms and differences in pubertal development, neuropsychological functioning, affective styles, coping and socialization have been identified. Longitudinal analyses now will examine biological and environmental factors that contribute to increases, decreases, shifts, and lack of change in psychiatric symptoms and psychological problems over time. When these longitudinal analyses are completed they will help to illuminate the interaction of biological factors and socialization experiences that influence the form of expression of psychopathology in adolescent males and females.